Only seconds after the kickoff, the Nigerian striker flagrantly extended his arm while diving to poke home from point-blank range, a strike that was enough for the hosts to reach the competition final.
The game was notably ill-tempered as it witnessed a number of rows between both teams. The visitors protested against many refereeing decisions too.
Ahli played over an hour with ten men after mercurial midfielder Mohamed Barakat was sent off in the first half.
Geddo was deployed as a lone striker as the injuries of Francis Doe and Mohamed Talaat left Ahli coach Hossam Al-Badri short of frontline options.
Red Devils goalie Sherif Ekrami was persistently targeted with a laser pen during the match. Ahli's players were also teased by the green beam in set-pieces.
Furthermore, it was teeming with rain in Rades throughout the game.
It's the fourth time for one-time African champions Esperance to qualify for the Champions League final.
They won the continental title in 1994 and finished runners-up in 1999 and 2000.
Ahli beat Esperance 2-1 in the first leg of the CAF Champions League semi finals a fortnight ago. One goal was enough for the Tunisian side to go through on the away-goal rule.
Esperance will face defending champions TP Mazembe in the final.
Extremely Lively
From the outset Esperance looked extremely lively. They set the game alight after taking the lead in the first minute.
A corner kick, which was also illegitimate, was headed by Khaled Korbi towards Eneramo who handled the ball to give the hosts an early lead.
The away team players tried to convince referee Joseph Lamptey that the ball touched Eneramo's forearm, albeit to no avail.
For a while, the Cairo giants seemed to be able to equalize but recurring mistakes in midfield gave the hosts the opportunity to take control of the match.
Geddo came close to hitting a leveler after four minutes when he went one-on-one with keeper Wissem Naouali, who bravely blocked the Egypt international effort.
Shortly afterwards, a curling corner-kick from Ahmed Fathi could have brought the score level too when a kicked clearance from the goalie hit the post before going wide.
Esperance retaliated when Mejdi Ettraoui tried his luck in the 10th minute with a powerful shot that missed the target by inches.
Barakat Dismissal
Much to Ahli's woes, Barakat was sent off on the half-hour mark after thumping Korbi in the face during an off-ball scuffle.
Sherif Abdul-Fadil received a yellow card for a harsh challenge, which prompted Ahli's players to round the referee in anger.
With players pushing each other from both sides, Barakat was caught by TV cameras hitting Korbi, who seemingly pretended to be suffering acute pains.
Late in the first period, Geddo penetrated the area singlehandedly but once again was kept at bay.
Eneramo could have doubled Esperance's lead from inside the area when his low effort went past the post.
Tempo Slowed Down
The match's tempo was clearly slowed down after the interval.
Esperance kept the upper hand while an off-form Ahli side tried in vain to restore parity.
The energetic Geddo earned a free kick on the edge of the area. Mohamed Abou-Treika took it but missed the goal by quite some distance.
Al-Badri sent Mohamed Fadl and Shehab Ahmed into battle instead of Sayed Moawad and Abou-Treika respectively. Both substitutions barely increased Ahli's firepower
Fadl and Geddo combined well ten minutes from time when they exchanged passes before the latter was nutmegged in the area.
The six-time African champions kept trying to cancel out their opponents' slender lead till the last minute.